Self-ratings of olfactory function reflect odor annoyance rather than olfactory acuity.
OBJECTIVE
Self-ratings of olfactory function often correlates poorly with results of objective smell tests. We explored these ratings relative to self-rating of odor annoyance, to odor identification ability, and to mean perceived intensity of odors, and estimated relative genetic and environmental contributions to these traits.


METHODS
A total of 1,311 individual twins from the general population (62% females and 38% males, aged 10-83 years, mean age 29 years) including 191 monozygous and 343 dizygous complete twin pairs from Australia, Denmark, Finland, and the United Kingdom rated their sense of smell and annoyance caused by ambient smells (e.g., smells of foods) using seven categories, and performed odor identification and evaluation task for six scratch-and-sniff odor stimuli.


RESULTS
The self-rating of olfactory function correlated with the self-rating of odor annoyance (r = 0.30) but neither correlated with the odor identification score. Quantitative genetic modeling revealed no unambiguously significant genetic contribution to variation in any of the studied traits.


CONCLUSIONS
The results suggest that environmental rather than genetic factors modify the self-rating of olfactory function and support earlier findings of discrepancy between subjective and objective measures of olfactory function. In addition, the results imply that the self-rating of olfactory function arises from experienced odor annoyance rather than from actual olfactory acuity.
Knaapila
Antti
A
Department of Food Technology, University of Helsinki, Helsinki, Finland. antti.knaapila@helsinki.fi
Tuorila
Hely
H
Kyvik
Kirsten O
KO
Wright
Margaret J
MJ
Keskitalo
Kaisu
K
Hansen
Jonathan
J
Kaprio
Jaakko
J
Perola
Markus
M
Silventoinen
Karri
K
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001290:Attitude; D002648:Child; D004192:Discrimination, Psychological / Q000502:physiology; D004200:Diseases in Twins / Q000175:diagnosis / Q000235:genetics / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009812:Odorants; D000857:Olfaction Disorders / Q000175:diagnosis / Q000235:genetics / Q000523:psychology*; D011237:Predictive Value of Tests; D012684:Sensory Thresholds / Q000502:physiology; D012903:Smell / Q000235:genetics; D012931:Social Environment; D013694:Temperament; D055815:Young Adult